Device and method for preprocessing prior to coding of a sequence of images

Abstract

The invention relates to a method and a device for preprocessing prior to coding of a sequence of images. the device comprises means of estimation of motion, for each pixel of the current frame, between the current pixel and the corresponding pixel of the previous frame and of the previous frame of like parity.

1 . Device for preprocessing prior to coding of a sequence of images comprising 
 means of estimation of motion, for each pixel of the current frame, between the current pixel and the corresponding pixel of the previous frame and of the previous frame of like parity,    wherein it comprises    means of performing a morphological processing on the pixels of the current frame with the aid of a structuring element,    means of defining the pixels of the structuring element on which the said morphological processing is performed by the means of morphological processing as a function of the motion estimation carried out on the current pixel.    
   
   
       2 . Device according to  claim 1 , wherein it comprises 
 means of detecting whether the current pixel is regarded as forming part of a motionless zone, said to be fixed, with respect to the previous frame and with respect to the previous frame of like parity,    means of comparing with a first predetermined threshold the motion of the current pixel with respect to its position in the previous frame and with a second predetermined threshold with respect to its position in the previous frame of like parity.    
   
   
       3 . Device according to  claim 2 , wherein the means of comparing with a predetermined motion threshold the motion of the current pixel with respect to the previous frame and with respect to the previous frame of like parity compare a vector modulus calculated over a neighbourhood of the current point with the said predetermined thresholds.  
   
   
       4 . Device according to  claim 3 , wherein the means of defining the pixels of the structuring element for the current pixel are suitable for forming a structuring element comprising three pixels.  
   
   
       5 . Device according to  claim 4 , wherein the means of defining the pixels of the structuring element for the current pixel are suitable for selecting 
 the current pixel, and    if the current pixel forms part of a fixed zone with respect to the previous frame, the pixel of the previous frame with the same coordinates as the current pixel, otherwise the pixel of the previous frame, translated by the motion vector, and    if the current pixel forms part of a fixed zone with respect to the previous frame of like parity, the pixel of the previous frame with the same coordinates as the current pixel, otherwise the pixel of the previous frame of like parity, translated by the motion vector.    
   
   
       6 . Device according to  claim 5 , wherein it comprises means of validating, as a function of the comparison with a predetermined threshold, the pixels selected so as to define the structuring element.  
   
   
       7 . Device according to  claim 6 , wherein the means of validating the pixels selected are suitable for validating 
 the pixel selected at the previous frame if the vector modulus is greater than the first predetermined threshold,    the pixel selected at the previous frame of like parity if the vector modulus is greater than the second predetermined threshold.    
   
   
       8 . Device according to  claim 1 , wherein the means of performing a morphological processing are suitable for performing, on the structuring element, successively an erosion operation followed by a dilatation operation followed by an erosion operation followed by a dilatation operation.  
   
   
       9 . Method of preprocessing prior to coding of a sequence of images comprising a step of estimation of motion, for each pixel of the current frame, between the current pixel and the corresponding pixel of the previous frame and of the previous frame of like parity,  
     wherein it comprises the steps of 
 morphological processing of the pixels of the current frame with the aid of a structuring element,  
 defining the pixels of the structuring element on which the said morphological processing is performed during the step of morphological processing as a function of the motion estimation carried out on the current pixel.